CDC Recommends Gamma Release Assay (IGRA) for TB

New guidelines from the Centers for Disease Control and Prevention (CDC) that recommend interferon-gamma release assay (IGRA) blood tests over the century-old tuberculin skin test (TST) to detect Mycobacterium tuberculosis (TB) could help hospitalist groups save time and money, according to the head of a TB institute.

The guidelines, published in the CDC’s Morbidity & Mortality Weekly Report, recommend providers use IGRAs over TSTs for certain populations, including patients who historically are unlikely to return for a needed second visit to read the TST results and patients who have previously received Bacille Calmette-Guérin (BCG) as a vaccine or as a cancer therapy (MMWR Recomm Rep. 2010;59(RR-5):1-25).

TSTs remain the preferred test for children younger than 5 years old, although some research has suggested that using both tests in youngsters could increase diagnostic sensitivity for that population.

Lee B. Reichman, MD, MPH, FACP, FCCP, of New Jersey Medical School’s Global Tuberculosis Institute in Newark says the improved efficacy of IGRAs should help weed out the false positives associated with the TSTs. That should be a boon for hospitalists looking to boost cost efficiency by focusing care delivery on the most at-risk populations, he adds.

“The hospitalist is busy,” Dr. Reichman says. “So now he doesn’t have to worry about all those people who are turning out to be a false positive.”

Dr. Reichman hopes the new guidelines catch on quickly, particularly because IGRAs must be conducted in laboratory settings that help ensure better predictive results. He fears, however, that adherence to traditional methods like BCG vaccination, which is particularly popular in Europe, might stall widespread IGRA adoption.

“It will take time to get there,” he says. “The TB community is notoriously slow in adapting new technologies.”